Field of the Invention
The present invention relates to a multilayer ceramic capacitor.
Description of the Related Art
A multilayer ceramic capacitor generally has a capacitor body of laminate structure and a pair of external electrodes, and constitutes a roughly rectangular solid shape defined by its length, width, and height. The capacitance of such a multilayer ceramic capacitor is ensured by the capacitive part of the capacitor body, or specifically by an area where multiple internal electrode layers are stacked with dielectric layers sandwiched in between.
Multilayer ceramic capacitors of this type are still facing strong demand for larger capacitance, and one effective way to satisfy this demand is to reduce the thickness of the dielectric layers present between the internal electrode layers in the capacitive part. In light of the general properties of dielectric materials, however, making the dielectric layers in the capacitive part thinner to 1.0 μm or less, for example, will likely cause the insulation resistance to decrease, although doing so will increase the capacitance. In other words, since increasing the capacitance by reducing the thickness of the dielectric layers will cause the insulation resistance to decrease, the CR product (product of capacitance and insulation resistance) representing the characteristics of the multilayer ceramic capacitor may drop, even to below an acceptable range.
Patent Literature 1 cited below describes an invention aimed at preventing the CR product from dropping by limiting the grain size and volume ratio of the crystal grains contained in the dielectric layer whose thickness is 2.5 μm or less; however, accurately limiting the grain size and volume ratio of the crystal grains is difficult in consideration of the manufacturing method, which makes it difficult to improve the CR product as expected.